Electric incandescent lamp



May 24, 1966 c. FANTUR ELECTRIC INCANDESCENT LAMP Filed Nov. 26, 1962 Invervtov. Charles LFan tuv 9 9- 7 IS A tovneg United States Patent 3,253,178 ELECTREC INCANDESCENT LAMP Charles L. Fantur, South Euclid, Ohio, assignor to General Electric Company, a corporation of New York Filed Nov. 26, 1962, Ser. No. 239,975 7 Claims. (Cl. 313271) This invention relates in general to electric incandescent lamps and more particularly to a mount construction therefor.- The invention is of particular applicability to incandescent lamps of the type conventionally used in certain optical apparatus such as oscillographs or galvanometers of the light-beam type wherein the light from a straight wire filament in the lamp is reflected by the galvanometer mirror into a screen or into a light-sensitive recording tape or paper chart on which it is focused to produce a point image of the filament.

As generally constructed heretofore, incandescent lamps designed for use in such light-beam type oscillographs or galvanometers have employed a mount structure comprised of a straight wire filament supported at one end by a comparatively long inner lead-in wire extending into the lamp envelope or bulb from the pressed seal or stem press thereof. With such prior mount constructions, the filament-supporting free end of the long inner leadin wire is readily subject to vibration under the slightest physical shock imparted to the lamp, which vibration is then transmitted to the filament. Such filament vibration is highly objectionable for the reason that it is apt to cause the filament to be displaced out of the focus or field of view of the oscillograph mirror or mirrors.

It is an object of my invention, therefore, to provide an electric incandescent lamp of the character referred to above having a substantially vibrationless mount construction.

Another object of my invention is to provide an electric incandescent lamp of the character referred to above having a straight wire filament which is substantially vibration-free in at least one transverse direction.

Still another object of my invention is to provide an electric incandescent lamp of the character referred to above having a filament-supporting structure effective to prevent vibration of the straight wire filament in at least one transverse direction and to also maintain it in a taut position at all times.

Briefly stated, in accordance with one aspect of the invention, the straight refractory metal wire filament of an electric incandescent lamp of the type referred to hereinabove is kept substantially free from vibration, in at least one direction transversely thereof, by having the end thereof remote from the pressed seal or stem press of the lamp connected to and rigidly supported from, and at approximately the intersecting ends of, a pair of convergent rigid straight wire supports which are joined at their intersecting ends and are rigidly supported at their other or divergent ends from respective rigid anchor wire portions embedded in the pressed seal or stem press of the lamp. The other end of the filament is connected, as customary herebefore, to one end of a tension coil spring which is connected at its other end to a rigid lead-in conductor sealed through the pressed seal or stem press of the lamp and serves to maintain the straight wire filament under tension at all times. At least one of the convergent wire supports and its respective anchor wire portion serves as the other lead-in conductor for the filament, for which purpose such anchor wire portion is extended outwardly through the pressed seal of the lamp.

Further objects and advantages of the invention will appear from the following detailed description of species thereof and from the accompanying drawing.

In the drawings, FIG. 1 is a front elevation of an Patented May 24, 1966 electric incandescent lamp provided with a mount structure according to the invention.

FIG. 2 is a side elevation of the lamp shown in FIG. 1, and

FIG. 3 is a side elevation of a modified form of lamp mount structure according to the invention.

Referring to the drawing, the electric incandescent lamp there shown comprises a sealed glass envelope or bulb 1, preferably of tubular shape as shown, having at one end a neck portion 2 provided with a reentrant glass stem tube 3 which extends into the envelope approximately axially thereof and terminates at its inner end in a pressed seal or stem press portion 4. Disposed Within the envelope 1 is a lamp mount 5 according to the invention and comprising a pair of wire conductors 6, 7 having rigid anchor wire portions 8 and 9, respectively, embedded in and rigidly supported from the stern press 4 and extending endwise therefrom into the envelope approximately in a common axial plane thereof. The anchor wire portions 8 and 9 may conveniently be constituted, for example, of nickel wire having a diameter of around 35 to 40 mils or so. Also sealed through the stem press 4 is a lead-in wire or conductor 10 having a rigid inner lead portion 11 rigidly supported from the stem press and extending end-wise therefrom into the envelope but offset, as shown in FIG. 2, to one side of the plane of the anchor wires 8, 9. The inner lead portion 11 may be conveniently constituted of, for instance, nickel wire of a diameter around 25 mils. The lead-in wire 10 is connected at its outer end to an end contact terminal 12 of a standard prefocus type lamp base 13 provided with a prefocus flange 14 and suitably secured, as by means of a conventional basing cement for instance, to the neck end of the lamp envelope. One or, as shown, both of the wire conductors 6, 7 are connected at their outer ends to the other end contact terminal 15 of the lamp base 13 to serve as the other lead-in wire for the lamp.

Disposed within the envelope 1 is a filament 16 com prising a straight length of refractory metal wire such as tungsten wire supported on the lamp mount 5 in a position extending approximately longitudinally but, as shown in FIG. 2, preferably offset a slight distance to one side of the approximately coincident axes of the stem tube 3 and the tubular envelope 1. The end of the filament nearest the stern press 4 is supported from and electrically connected to the rigid inner lead portion 11 of the lead-in wire 10 through a tension coil spring 17 of tungsten or other refractory metal wire which acts to exert tension on the filament so as to 'hold it taut at all times. The other end of the filament 16 farthest from the stern press 4 is supported, in accordance with the invention, by a supporting structure 18 of substantially vibrationless character, at least in one direction transversely of the filament, whereby the filament is kept from vibrating in such transverse direction when the lamp is subjected to the physical shocks normally encountered in service. To this end the wire conductors 6, 7 are provided with relatively long and rigid straight wire support portions 19 and 20, respectively, which may be conveniently constituted, for example, of nickel wire of a diameter around 25 mils or so and which are rigidly supported from the anchor portions 8, 9 and extend inwardly of the envelope therefrom in a direction generally longitudinally of the stem tube 3 and the envelope 1 so as to lie in a plane approximately parallel to and preferably including the approximately coincident axes thereof. As shown in FIG. 1, the pair of Wire supports 19, 20 converge at a slight angle of around 15 to 20 so as to intersect one another at a point 21 appreciably removed from the stem press 4, and they are integrally joined at their intersection 21 as by being welded together therea-t.

The end of the filament 16 farthest from the stem press 4 is electrically connected to and rigidly supported from the pair of wire supports 19, 20 at a point adjacent their intersection 21. For such purpose, the convergent wire supports 19, 20 may be provided, at their intersection 21, with a laterally extending rigid support leg 22 to which the filament 16 is connected. The support leg 22 may be conveniently constituted by a laterally bent extension of one of the wire supports 19, 20, e.g., the support wire 19,

' as shown.

To additionally stiffen or brace the wire frame filamentsupporting structure '18 against vibration in the plane thereof, a rigid bridge or brace member 23, which may be conveniently constituted by a straight length of rigid wire such as nickel wire of a diameter of around 25 mils, is connected across the wire supports 19, 20 at the points where their divergent ends join with the rigid anchor wires 8, 9. Thus, as will be evident from FIG. 1, the brace member 23, along with the two wire supports 19, 20, together form the three sides of a triangular filament-supporting wire frame in the general shape of an isosceles triangle of which the brace member 23 constitutes the base side and the two wire supports 19, 20 constitute the opposite equal sides which converge and intersect to form the vertex 21 of the triangle. Although the triangular wire frame 19, 20 and 23 may be formed of a single length of wire bent to the final triangular shape, or of separate straight lengths of wire welded or otherwise rigidly joined together, it is preferable for reasons of manufacturing simplicity and cost saving to form it in the manner shown in FIGS. 1 and 2 wherein one of the wire supports 19, together with the brace wire 23 and the top lateral support leg 22, are all formed of a single length of wire which is suitably bent into the desired final shape and secured at the opposite ends of the brace wire 23, as by welding for example, to the two anchor wires 8, 9. The other wire support 20 is then formed of a straight length of wire welded at one end to the junction of the anchor wire 9 and brace wire 23, and at its other end to the wire support 19 at a point 21 adjacent the laterally bent end leg.

22 thereof.

As shown in FIGS. 1 and 2, the straight wire filament 16 is supported by the inner lead 11 and the converging wire supports 19, 20 in a position extending generally lengthwise of the wire supports 19, 20 and parallel both to the approximately coincident axes of the stem tube 3 and the envelope 1 and to the plane of the converging Wire supports 19, 20 or triangular wire support frame 18. Also, while the filament may extend approximately coincident with the approximately coincident axes of the stem tube 4 and envelope 1, it is preferably offset as shown in FIG. 2 a slight distance up to inch or so (for example, around fii inch in the particular case illustrated) to one side of the plane of the wire supports 19, 20 or triangular wire support frame 18. In addition, for the purposes of the invention, the filament 16 is disposed in a plane approximately bisecting the angle between, and preferably approximately normal to the plane of the converging wire supports 19, 20 or support frame 18. In other words, the filament lies in a plane which approximately bisects the vertex angle of the triangular wire frame 18 at the intersection 21 of the wire supports 19, 20 and which is preferably normal to the plane of the triangular wire frame.

To eliminate objectionable specular reflections of the filament 16 off the wall of the glass envelope 1, the back side of the tubular envelope, opposite the front side thereof through which the filament is to be viewed by the reflecting mirror of an oscillograph or recording galvanometer, may be made light-diffusing, as by being inside frosted for example, as indicated at 24. As shown in FIG. 2, the cut-off line 25 of the light-diffusing or frosted portion 25 of the envelope lies in' a plane which is generally parallel to the plane of the wire frame 1'8but' offset a slight distance therefrom to that side thereof opposite from the filament 16.

It will be appreciated that, with a mount structure such as described hereinabove, the converging wire supports 19, 20 together constitute, in effect, a bipod type of support for the upper end of the filament 16 farthest from the stem press 4. Because of the mutual bracing effect of the two converging Wire supports 19, 20 on one another, such a bipod support is therefore much less apt to undergo transverse vibration in the general direction of the plane of the wire supports 19, 20, under the influence of physical shocks imparted to the lamp, than, a single long filamentsupporting lead-in wire extending into the envelope from the stem press and supported therefrom, as in the case of the prior type lamp constructions. As a result, the filament 16 of a lamp constructed according to the invention is kept substantially free from transverse vibration in at least those axial planes of the filament which extend generally parallel to the plane of the converging wire supports 19, 20, thereby preventing displacement of the filament out of the focus or field of view of the reflecting mirror of an oscillograph or recording galvanometer with which the lamp may be used.

To prevent the filament 16 from transverse vibration in directions normal to as well as parallel to the plane of the two converging wire supports 19, 20, a third rigid straight wire support 26, similar to and converging toward the wire supports 19, 20, may be incorporated in the wire support frame 18, as shown in the modified form of mount structure 27 illustrated in FIG. 3. This third rigid wire support 26 is disposed in a plane normal to the plane of, and bisectin g the angle between the two converging wire supports 19, 20, and it converges toward and intersects the wire supports 19, 20 approximately at their intersection or juncture 21 where it is rigidly joined together therewith, as by being welded thereto, to thereby form together with the two wire supports 19, 20 a tripod type of support means for the end of the filament farthest from the stem press 4. Like the wire supports 19, 20, the third wire support 26 is rigidly supported at its divergent end from an anchor wire portion 28 embedded in the stem press 4. As shown, the third wire support 26 and its anchor wire support portion 28 may be constituted by separate lengths of wire suitably joined together, as by welding for instance. The tripod type wire support H frame 18' for the filament as shown in FIG. 3 affords a substantially vibrationless support for the filament such as prevents the vibration thereof in all directions transversely thereof, under the physical shocks normally imparted to the lamp in service.

Although a preferred embodiment of my invention has been disclosed, it will be understood that the invention is not to be limited to the specific construction and arrangement of parts shown, but that they may be widely modified within the spirit and scope of my invention as defined by the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric incandescent lamp comprising a sealed glass envelope having a pressed seal portion, a pair of wire conductors each comprising a rigid anchor portion embedded in said pressed seal and a rigid straight wire support portion extending inwardly of the envelope and rigidly supported from said anchor portion, said straight wire support portions converging toward and intersecting one another inwardly of the envelope and being rigidly joined together at their intersection, a lead-in wire sealed through said pressed seal, and a filament in said envelope comprising a straight length of refractory metal wire connected at one end to said'lead in wire and having its other end connected to and rigidly supported from the said convergent wire support portions adjacent their intersection, said wire filament extending generally lengthwise of the said convergent wire support portions and being disposed in a plane approximately bisecting the angle between the said convergent wire support portions, at least one of said wire conductors being sealed through said pressed seal and constituting the other lead-in wire for said filament.

2. An electric incandescent lamp as specified in claim 1 wherein the said filament is offset to one side of, and is disposed in a plane extending approximately normal to, the plane of the said convergent wire support portions.

3. An electric incandescent lamp comprising a sealed glass envelope having a pressed seal portion, a pair of rigid anchor wires embedded in said pressed seal and extending into said envelope, a pair of rigid straight wire supports unitary with and extending from respective ones of said anchor wires inwardly of said envelope in convergent intersecting relation and joined together at their intersection, a lead-in wire sealed through said pressed seal portion, a filament in said envelope comprising a straight length of refractory metal wire connected at one end to and rigidly supported from the said convergent wire supports adjacent their intersection, and a tension coil spring connecting the other end of said filament to the said leadin wire to exert tension on the filament so as to hold it taut, said Wire filament extending generally lengthwise of the said convergent Wire supports and being disposed in a plane approximately bisecting the angle between the said convergent wire supports, at least one of said convergent wire supports and its respective anchor wire together constituting the other lead-in wire for said filament.

4. An electric incandescent lamp as specified in claim 3 wherein the said filament is offset to one side of, and is disposed in a plane extending approximately normal to, the plane of the said convergent wire supports.

5. An electric incandescent lamp comprising a sealed glass envelope provided with a re-entrant glass stem tube terminating inwardly of the envelope in a stem prms, a pair of rigid anchor wires sealed in said stern press and extending into the envelope, a rigid bridge member connected across the said anchor wires inwardly of said envelope, a pair of rigid straight wire supports unitary with respective ones of said anchor wires and extending therefrom, at points adjacent their connection to said bridge member, in a direction generally longitudinally of said stem tube and approximately in a common plane parallel to the axis thereof, said Wire supports converging at a slight angle toward one another and intersecting at a point removed from said stem press, said Wire supports being rigidly joined together at their said intersection, a lead-in wire sealed through said stem press, and a filament in said envelope comprising a straight length of refractory metal wire connected at one end to said lead-in Wire and having its other end connected to and rigidly supported from the said convergent wire supports adjacent their said intersection, said filament extending generally parallel to the axis of said stem tube and being disposed to one side of the plane of the said convergent wire supports, at least one of said convergent wire supports and its respective anchor Wire together constituting the other lead-in Wire for said filament.

6. An electric incandescent lamp comprising a sealed glass envelope provided with a re-entrant glass stem tube terminating inwardly of the envelope in a stem press, a pair of rigid anchor wires sealed in said stem press and extending into the envelope, a rigid bridge member connected across the said anchor wires inwardly of said envelope, a pair of rigid straight wire supports unitary with respective ones of said anchor wires and extending therefrom, at points adjacent their connections to said bridge member, in a direction generally longitudinally of said stem tube and approximately in a common plane parallel to the axis thereof, said wire supports converging at a slight angle toward one another and intersecting at a point removed from said stem press, said wire supports being rigidly joined together at their said intersection, a leadin wire sealed through said stem press, a filament in said envelope comprising a straight length of refractory metal wire connected at one end to and rigidly supported from said convergent wire supports adjacent their said intersection, and a tension coil spring connecting the other end of said filament to the said lead-in wire to exert tension on the filament so as to hold it taut, said filament extending generally parallel to the axis of said stem tube and being disposed to one side of the plane of said convergent wire supports and in a plane approximately normal to the plane of and approximately bisecting the angle between the convergent wire supports, at least one of said convergent wire supports and its respective anchor wire together constituting the other lead-in wire for said filament.

7. An electric incandescent lamp comprising a sealed glass envelope having a pressed seal portion, a pair of rigid anchor wires embedded in said pressed seal and extending into said envelope, a triangular rigid wire frame in the general shape of an isosceles triangle secured and supported at the opposite ends of its base side on said support wires, a lead-in conductor sealed through said pressed seal, and a filament comprising a straight length of refractory metal wire connected at one end to the said lead-in conductor and having its other end connected to and rigidly supported from the said triangular wire frame adjacent the vertex thereof opposite its base side, said Wire filament extending generally parallel to the plane of said triangular wire frame and being disposed in a plane approximately normal to the plane of and approximately bisecting the vertex angle of said triangular wire frame, at least one of said anchor wires together with said wire frame constituting the other lead-in conductor for said filament.

No references cited.

JOHN W. HUCKERT, Primary Examiner.

R. F. POLISSACK, Assistant Examiner. 

1. AN ELECTRIC INCANDESCENT LAMP COMPRISING A SEALED GLASS ENVELOPE HAVING A PRESSED SEAL PORTION, A PAIR OF WIRE CONDUCTORS EACH COMPRISING A RIGID ANCHOR PORTION EMBEDDED IN SAID PRESSED SEAL AND A RIGID STRAIGHT WIRE SUPPORT PORTION EXTENDING INWARDLY OF THE ENVELOPE AND RIGIDLY SUPPORTED FROM SAID ANOTHER PORTION, SAID STRAIGHT WIRE SUPPORT PORTIONS CONVERGING TOWARD AND INTERSECTING ONE ANOTHER INWARDLY OF THE ENVELOPE AND BEING RADIALLY JOINED TOGETHER AT THEIR INTERSECTION, A LEAD-IN WIRE SEALED THROUGH SAID PRESSED SEAL, AND A FILAMENT IN SAID JOINED COMPRISING A STRAIGHT LENGTH OF REFRACTORY METAL WIRE CONNECTED AT ONE END TO SAID LEAD-IN WIRE AND HAVING ITS OTHER END CONNECTED TO AND RIGIDLY SUPPORTED FROM THE SAID CONVERGENT WIRE SUPPORT PORTIONS ADJACENT THEIR INTERSECTION, SAID WIRE FILAMENT EXTENDING GENERALLY LENGTHWISE OF THE SAID CONVERGENT WIRE SUPPORT PORTIONS AND BEING DISPOSED IN A PLANE APPROXIMATELY BISECTING THE ANGLE BETWEEN THE SAID CONVERGENT WIRE SUPPORT PORTIONS, AT LEAST ONE OF SAID WIRE CONDUCTORS BEING SEALED THROUGH SAID PRESSED SEAL AND CONSTITUTING THE OTHER LEAD-IN WIRE FOR SAID FILAMENT. 